Ferrite testing
Ferrite testing
(OP)
Can some explain to me how do we perform a Ferrite test? and what is purpose having this test
Thanks
Thanks
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
|
RE: Ferrite testing
"When the eagles are silent, the parrots begin to jabber."
Winston Churchill
RE: Ferrite testing
Duplex SS nominally contains 50% ferrite/austenite, although the acceptable range for ferrite is much broader than exactly 50%.
There are several ways to measure the FN. As mentioned by Metalguy, you can use a Magne-Gage. I have used a Severn Gage and a Feritscope.
RE: Ferrite testing
The FN and the actual volume fraction of ferrite are not exactly the same, so pick one system and stick with it.
= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net
RE: Ferrite testing
RE: Ferrite testing
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Ferrite testing
Cast austenitic stainless steels typically have anywhere from 8-18% ferrite in them. This is due to the alloy balance (chemically), but is also advantageous when welding the materials and during the solidification. As a result, cast "stainless steels" (austenitic) will draw a magnet lightly.
Duplex stainless steels are even more important to measure the ferrite. The reason is that the ferrite can vary over a wide range (from as low as the low 40's to as high as the 60% range). Lower ferrite readings in duplex stainless steels can indicate a real potential problem. Improperly heat treated (insufficient cooling rate) duplex stainless steels can have sigma phase or other deleterious phases that can embrittle the material and cause catastrophic mechanical failures (not to mention the loss of the desired corrosion resistance).